Clamp-type electrical terminals

ABSTRACT

Clamp-type electrical terminals of the type typified by alligator clips include one or more resilient conductive pads against which a wire or other device being connected will be compressed, so that very fine wires may be securely held.

United States Patent Kurtz [4 Mar. 14, 1972 [54] CLAMP-TYPE ELECTRICAL 1,513,009 10/1924 Robb ..24/262 GC TERMINALS 3,374,455 3/1968 Sullivan et a1. ..339/31 810,678 l/1906 Rubin ..339/262 GC [72] Inventor: John O. Kurtz, PO. Box 79, Smithvllle Flats, NY. 13841 FOREIGN PATENTS OR APPLICATIONS [22] Filed: June 26, 1970 409,047 9/1966 Switzerland ..339/95 R [2]] Appl' NO; 50028 Primary Examiner loseph H. McGlynn AttorneyRichard G. Stephens [52] US. Cl. ..339/95 R, 24/262 R, 324/725,

339/108 TP, 339/200 P, 339/255 P, 339/260 [57] ABSTRACT [51] Int. Cl ..H0lr 9/12 58 Field of Search ..339/95, 108, 255, 260, 261, yp electrical termmals of the y yp y alliga- 33 2 g 200; 24 73 SA, 31 LC, 243 LC 24 C tor clips include one or more resilient conductive pads against 262; 324/725, 149 which a wire or other device being connected will be compressed, so that very fine wires may be securely held. 6 R f 'ted [5 1 e 20 Claims, 24 Drawing Figures UNITED STATES PATENTS 3,032,849 5/1962 Cohen et a1 ..24/262 R PAIENTEDMAR 14 m2 3, 649 954 sum 1 or 3 FIG. la

ll L 4 FIG. lc

II l5 l4 FIG. 20. FIG. 2c Prior Arr JOHN O. KURTZ ham PAIENTEDIIAR 14 I972 13, 649,954

sum 3 [IF 3 FIG. 50. FIG. 5b FIG. 5c

FIG 60.

CLAMP-TYPE ELECTRICAL TERMINALS This invention relates to detachable electrical terminals, and more particularly, to clamp-type terminals such as alligator clips, F ahnestock clips and the like, wherein a spring forces two members toward each other to clamp an electrical conductor between the members. Alligator clips commonly comprise a pair of members each having serrated edges, with the members both pivotally mounted on a shaft and urged by a spring so that the serrated edges of the two members are urged together. If such clips are fabricated and assembled with great precision, it is possible for the teeth on one member to mesh precisely with the teeth on the other member, so that the jaws will fully close together along the entire length of their serrated edges, and under such conditions such a clip will securely grip any of a wide variety of sizes of wires and terminals and the like. Manufacturing tolerances, however, and/or wear or deformation which occurs during use, often result in the opposing teeth of a pair of jaws not fully meshing, so that gaps exist between various of the teeth when the spring has closed the jaws as much as they will close. A pair ofjaws tends to close, of course, only until a tooth on one jaw strikes a portion of a tooth on the other jaw, and at that time a large number of gaps may remain between the other teeth on the two jaws. Such gaps cause no great problem when a clip is intended to engage conductors which are substantially greater in crosssection than any of the gaps. However, the occurrence of gaps when a clip is intended to be fully closed frequently makes it difficult or impossible for such a clip to securely engage very fine wires. When a clip fails to securely g'n'p such a fine wire, erroneous and intermittently-changing readings may occur on a voltmeter or the like. The increasing amount of miniaturization used in electronic circuits has resulted in the use of many fine wires, such as transistor and integrated circuit leads, which cannot be securely gripped by many alligator clips of the prior art without a large amount of tedious testing to determine which surfaces of the clip are mating first. It is one object of the present invention to provide improved alligator clips which are capable of securely gripping very fine wires and other very small conductors. It is another object of the invention to provide such a clip without the need for maintaining critical tolerances or precise alignment between the jaws of such a clip, so that the clips may be manufactured and assembled economically, and so that they will continue to function effectively even after they have been subjected to substantial wear and deformation.

Detachable clip leads by their very nature are ordinarily connected to a given point in an electronic circuit only temporarily, and in the typical usage of such leads a given clip on a test lead may be successively connected to a wide variety of different points in an electronic circuit, to successive conductors having a wide variety of sizes and shapes. It is another object of the invention to provide an improved spring-applied clip which can securely grip a wide variety of sizes of conductors, including relatively large conductors as well as the very small conductors which slip through the gaps presented by many prior art clips.

Many conductors to which one frequently desires to attach a clip lead sometimes carry a surface film which tends to prevent good electrical contact being made between such a conductor and the clip. While good contact can ordinarily be made on larger conductors, by rotating the clip while it grips the conductor so that the clipjaws scrape or wipe portions of the conductor, or by otherwise scraping the conductor with a knife or the like. Such techniques ordinarily apply a stress between the conductor and a device to which the conductor is attached. It is frequently very difiicult to clean a very small conductor, such as an integrated circuit lead, for example, by such techniques without breaking the lead from the integrated circuit, thereby destroying the integrated circuit. Thus it is another object of the invention to provide an improved springapplied test clip which will effectively and automatically wipe a conductor to which it is applied without requiring that appreciable stresses be applied between the conductor and the device or devices to which the conductor is attached.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the features of construction, combination of elements, and arrangement of parts, which will be exemplified in the constructions hereinafter set forth, and the scope of the invention will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention reference should be had to the following detailed description taken in connection with the accompanying drawings, in which:

FIG. la is a side view of one form of alligator clip constructed in accordance with the present invention, with portions of the jaws shown cutaway.

FIG. lb is a cross-section view of the clip of FIG. la taken at lines lblb in FIG. la. FIGS. 1c, 1d and 1e are enlarged portions of FIG. la shown in different relative positions as the clip of FIGS. la -ld is clamped upon a conductor.

FIG. 2a is a side view of one common form of prior an alligator clip.

FIG. 2b is an end view of the prior art clip of FIG. 2a.

FIG. 2c is an enlarged view of a portion of the prior art alligator clip of FIG. 2, showing how gaps may occur along the mating edges of the clip of FIGS. 2a and 2b when it is intended to be fully closed, and FIG. 2d shows how similar gaps may occur at the front edge of the clip.

FIGS. 3a and 3b are side elevation and top views of an alternative connector constructed according to the invention.

FIGS. 4a, 4b and 4c are side, top and end sectional elevation views, respectively of a further embodiment of the invention which performs both the functions of an alligator clip and a banana plug.

FIGS. 51:, 5b and 5c are side views of several forms of jaw and pad arrangements which may be used in accordance with the invention.

FIG. 6a is a side view of an improved form of battery clamp constructed in accordance with the invention, and FIG. 6b is an enlarged side view of a conductive wire pad portion of FIG. 6a.

FIGS 7a and 7b are top views of parts of one form of compressible conductive pad which may be used in various embodiments of the invention, and FIG. 7c is a side elevational view of a pad assembled from the parts of FIGS. 7a and 7b.

FIG. 8 is a diagrammatic view illustrating how pads used in various embodiments of the invention may be provided with a varying thickness to control the clamping force along their lengths.

FIG. 9 is a side view of an alternative form of compressible conductive pad in which the main portion of the spring force is provided with a non-conductive element.

The common prior art alligator clip of FIGS. 2a and 2b includes a pair of lever members 10 and 11 which are pivotally mounted relative to each other by means of a shaft or pin 12 which extends through holes through depending side flanges of each lever member. A coil spring (not shown) wound about pin 12 and carried between the side flanges of member 11 biases the two members so that their jaws, which are shown serrated, are urged together. A flexible lead wire (not shown) is ordinarily soldered, crimped or otherwise attached to member 10 at its rear end 10a, which is frequently formed to be cylindrical or tubular. By pinching the clip, so as to exert forces indicated by the arrows F, F, the jaws of the clip may be opened, against the force of the coil spring, so that a tenninal or conductor (not shown) may be introduced between the jaws, and upon release of the forces the coil spring will close the jaws to grip the terminal or conductor. The jaws are usually serrated, as shown, to present edges which will tend to bite into the grasped terminal, and to prevent small forces from dislodging the grasped terminal. The serrated edges commonly extend along both sides and across the front of each of the jaws. The spring force with which the clip grips a tenninal depends, of course, upon how far the jaws are pivoted from a fully closed position, and upon the distance of the grasped terminal from pin 12.

The serrated edges of such clips ordinarily grip large or moderate-size terminals with little difficulty, and large gaps are often left between portions of the serrated edges to allow large conductors to be gripped without opening the jaws so widely that extreme gripping force results. If very small wires or terminals are to be grasped by the clip, however, it is apparent that at least one pair of edges on the two jaws must be arranged to mate quite precisely, with little or no gap left between or adjacent the mating edges. While it is possible to fabricate such clips with a precision such that the serrated edges will mate with small gaps, such precision manufacturing is expensive, and wear and/or deformation which occurs during use of such clips frequently results in misalignment, so that many small gaps exist between opposing edges of the jaws. The pair of jaws tends to close, of course, only until a particular tooth on one jaw strikes a portion of a tooth on the other jaw, i.e., until point contact is made, and various sizes of gaps then exist between other opposing edges of the two jaws. FIG. 2c shows a portion of two slightly rnis-aligned or deformed jaws as they just contact each other. If an attempt were made to grip a very fine wire with the side of the clip, at point b in FIG. 2c, it will be seen that the jaws will force the fine wire leftwardly and downwardly rather than gripping it, and that an attempt to grip a fine wire between edges a and lle would similarly allow the fine wire to slip loose from the clip. Similarly, as shown in FIG. 2d, the failure of the serrated jaws to fully close leaves a number of gaps at the front of the clip which make it impossible to securely grip a very fine wire. Various spring-applied detachable connectors operate similarly to alligator clips but have flat surfaces or edges rather than serrated edges. These connectors also essentially tend to provide point contact between two parts, so that it is difficult to securely grasp a conductor between them unless one aligns the conductor very precisely with the portions of the connector which mate to fonn the point contact.

A central concept of the present invention involves the provision, in a spring-applied or clamp type electrical connector, of a resiliently compressible pad including a plurality of conductive wires, some of which will compressively grip a terminal or conductor, securely engaging it both mechanically and electrically at a multiplicity of contact points. Because such a pad will automatically change its shape to conform to a device which is urged against it, it is enabled to frictionally engage a terminal or conductor even in the face of substantial connector jaw misalignment.

FIGS. 10 and 1b illustrate an alligator clip connector in accordance with one form of the invention. The lever members 10 and I1 relatively pivot about pin 12 and are normally closed against each other by a coil spring (not shown) in identical fashion to the prior art device shown in FIG. 2a. The depending side flanges of the jaw portions of members 10 and 11 are shown cutaway in FIG. 1a, however, to disclose two resiliently compressible conductive wire pads 13 and 14. Conductive pad 13 is soldered, crimped or tack-welded to lever member 10, and pad 14 is similarly attached to member 11. As the coil spring drives the jaws toward each other, pads 13 and 14 eventually abut each other, and further closure of the jaws results in pads 13 and 14 being resiliently compressed. The jaws will be seen to close until the compressive force across the two pads provides a torque equal and opposite to that provided by the coil spring, or until rigid portions of the two jaws touch, whichever occurs first. Which will occur first depends upon the resilience of the pads and the spring constant of the coil spring, of course, as well as the spacing of opposing parts of the rigid jaws. If the pads are provided with sufficient resilience to provide a torque equalling the coil spring torque prior to engagement of any rigid jaw portions, it will be seen that a terminal or conductor gripped between pads 13 and 14 will be gripped with a force equal to the spring force, and the rigid jaw portions will not meet. Such an arrangement is assumed to be the case where the jaws take the form of FIG. 5b, or FIG. 50. FIG. 5b illustrates an embodiment where two separate pads carried on the two jaws meet to compress the terminal (not shown) therebetween, while FIG. 5c illustrates the use of a compressible conductive pad solely on one jaw, so that the terminal will be clamped between the pad and a rigid surface presented by the other jaw.

It is possible, however, to provide the conductive pads with less resilience or stiffness, so that the limit of closure results from the two jaws striking each other (or striking opposite sides of the terminal or conductor) at a time when the compressive force between the pads is far less than that required to oppose the coil spring, so that the terminal or conductor is gripped between the pads with a much lesser force. In arrangements of the latter type it is possible, by shaping the jaws of the connector, to provide two different types of operation. Firstly, if the jaws are provided with edges, such as the serrated edges shown in FIGS. 20 and 5a, the conductor or terminal being gripped can be gripped by such edges (with a force commen surate with that of the coil spring) as well as being squeezed between the two resilient pads with a lesser force. Because the conductive pads will then squeeze the portion of the terminal which they grip between them and prevent motion of that portion in the space between the jaws of the connector, they tend to prevent movement of the terminal within any gap which may exist between the teeth of the jaws, and hence it will be seen that the resilient pads not only grip the terminal themselves, but also aid the jaws to grip the terminal more securely.

Secondly, if the jaws are not provided with serrated edges or the like, but still provided with interengaging parts which limit jaw closure, it will be seen that the terminal will be gripped solely between the pads, with a force which may be arranged to be any desired amount less than the force provided by the coil spring. Even if teeth are not provided along the edges of the jaws, a limit stop acting between the jaws may be used to limit closure to a position at which the pads apply a desired force to a terminal squeezed between them. In FIG. la screw 16 threaded through member 10 acts as an adjustable limit stop against which member I 1 strikes to limit jaw closure. The use of screw 16 is optional, of course.

The resilient conductive wire pads are preferably formed of one or a few resilient wires having good conductivity, such as beryllium copper wires. The gauge of the wire will differ in different applications of the invention, of course. Fine wire of the order of No. 30 to No. 40 gauge is suitable for many applications. Wire having a good springiness but poorer conductivity, such as steel wire, may be plated to improve its conductivity and then used in certain applications. Solid (i.e., unplated) wire is preferred, however, so that wear does not reduce conductivity. Wire having a square, triangular or other noncircular cross-section, so as to provide sharp edges, is preferred. In various applications of the invention, the pads may take various shapes, such as rectangular or circular. One or several strands of wire may be laid in a cavity having the desired shape, with a given strand being bent so as to be trained back and forth and up and down in the cavity, thereby to provide an oversize, springy tangle" of wire. A die then may be forced into the cavity to compress the wire mass sufficiently to provide a set conforming to the desired shape, without completely crushing the mass so that it has no resilience. Use of a single piece or only a few strands for a given pad is ordinarily preferred, in order to minimize the number of loose ends, and the ends are poked or bent inside the tangle prior to compression, so that no loose ends will protrude from the finished pad, or at least the top and side edges of the pad. The ends may be welded together, of course, so as not to protrude. It is desirable that many sections of the wire be trained back and forth the top of the tangle, so that the finished pad will present a uniform surface without large holes.

Rather than essentially random formation as described above, the wire pads may be made by superimposing strips of loosely woven wire cloth or sheet, having warp strands running in one direction and woof strands perpendicular thereto, for example. The edges of the top sheet preferably are bent to cover the sides of the pad and tucked under the bottom of the pad, and soldered, brazed, crimped or tack-welded to the connector jaw. One or several strips of woven wire sheet may be used in similar fashion atop a tangle of wire to contain the tangle and to present a pad surface wherein the wires are spaced substantially uniformly. A form of compressible pad shown in FIG. 70 comprises a plurality of concentric coils of wire of the nature shown in FIG. 7a, atop which is placed the center section a of a cruciform shaped piece of woven wire mesh of the type shown in FIG. 7b, which is bent as shown by dashed lines in FIG. 7b. Portions b, c, d and e are bent downwardly to form the sides of the pad, and portionsf, g, h, and i are tucked underneath to form the bottom.

FIG. 9 shows a modified form of compressible, conductive pad formed by laying a plurality of closely-spaced fine wires 9, 9, (or a loosely woven fine-wire mesh) over a piece of compressible non-conductor, such as a piece of foam rubber 8. Unlike the previously-mentioned forms of pad, the major portion of the resilience of the pad of FIG. 9 is provided by the foam rubber rather than from wire resilience. In certain applications of the invention, wire pads of fine wire formed into small pads resembling steel wool pads in texture may be used.

FIGS. 10 le show portions of two jaws 10, 11 carrying respective compressible pads 13, 14 as the jaws successively close on a terminal post or wire 15. As the pads engage terminal 15 as shown in FIG. 1d they compress to partially surround the terminal, and as the pads are further compressed to the condition shown in FIG. 1e, a large plurality of wires engage and wipe terminal 15, so that a considerable contact surface area exists, as distinguished from the case with ordinary clip connectors, where two point contacts are established. Furthermore, while a simple cylindrical terminal 15 is assumed in FIGS. lc-le, the compressibility of the pads allows them to conform to a wide variety of different shapes of terminals and thereby provide substantial contact surface area.

The alternative device of FIGS. 3a and 3b is particularly useful where one of a number of closely-spaced terminals must be engaged by a test lead. A spring wire or flat blade 60 preferably formed of beryllium copper, is bent in a generally U-shaped form to provide a pair ofjaws 61, 62 one or both of which carries a wire mesh pad 63, only one such pad being shown in FIGS. 3a and 3b. The test lead 64 passes through a pair of essentially rigid hollow plastic tube pieces 65 and 66, and is soldered (or crimped) to wire 60 at its rear portion. Wire 60 is bent intermediate its ends, as at 60a and 60b, so that dimension a in FIG. 3a is greater than the inside diameter of outer tube 65 and the legs of wire 60 provide a pair of ramp edges 60c and 60d. Grasping lead 64 and pushing tube 65 forwardly (rightwardly as viewed in FIG. 3a) causes the right end of tube 65 to ride up the ramp edges, thereby squeezing the jaws together, and clamping the terminal (not shown) between the jaws. Tube 65 may be made long enough to completely cover wire 60 and even extend forwardly beyond the jaws of wire 60, so that wire 60 and the terminal are insulated from adjacent terminals. When tube 65 is pushed forward to cover wire 60, the spring compression of wire 60 pushes radially outward against the insides of tube 65, providing friction which holds tube 65 in place, with no tendency of tube 65 to move forwardly and rearwardly.

Inner tube 66 slidably mounted in outer tube 65 carries a tab 67 which extends radially outward through slot 68 in outer tube 65. In order to release the connector from the terminal without applying appreciable force to the terminal, tab 67 is pushed rightwardly until the right end of inner tube 66 butts against the rear end of wire 60. Tab 67 and inner tube 66 are then held stationary while outer tube 65 is slid leftwardly off of wire 60, allowing thejaws of wire 60 to open. Outer tube 65 is shown provided with a break 69 which opens into slot 68. Temporarily spreading the rear end of tube 65 at the break 69 allows tab 67 to be slid into slot 68 during initial assembly.

If a short length of rigid wire extending through tube 65 to approximately point 70 in FIG. 3a is used to connect the flexible test lead to U-shaped spring wire 60, inner tube 66 and the slot in outer tube 65 may be eliminated.

also is capable of functioning as a banana plug. A pair of lever members 71 and 72 are pivotally connected together by pivot pin 73, and a spring (not shown) wound around pin 73 and acting against members 7l and 72 urges their jaw portions together. One (or both) of the jaws carries a wire mesh pad, such as pad 74, so that the pad tends to be partially compressed by the force of the spring, and the wire mesh serves to insure good electrical and mechanical contact with a conductor gripped between the jaws, in the manner described above. The jaw portions of members 71 and 72 are formed semicylin drically in cross-section, as shown in FIG. 4c, and hence the device may be inserted in a round hole or conventional jack. Conventional banana plugs require specially formed slits and bends or flutes so that the plug will be resiliently deformed when inserted in a jack, both to cause plug portions to wipe inside surfaces of the jack, and to provide friction which will hold the plug in place in the jack. In the device of FIGS. 40-40 the spring force of the wire mesh pad (or pads) 74 urges the jaws of the plug against the sides of the jack, thereby eliminating any requirement that the jaws themselves be specially formed.

While the invention is particularly useful in connection with connectors intended to hold very small wires, the invention is not so limited, and basic principles of the invention may be applied to connectors such as those intended to grasp large battery terminals or positions of standard battery cable connectors. FIG. 6a shows a known form of clamp comprising a spring bar 20 having leg portions 20a, 20b which are forced apaJt by compression spring 21, thereby forcing together crossed end portions 20c, 2011. End portions 20c, 20d each carry a formed resilient wire pad 22a, 22b. Pad 22a, which is shown enlarged in FIG. 6b, includes an arcuate recess 23. When the clamp is clamped around a cylindrical battery terminal or a cylindrical portion of a standard battery cable connector, the resilient pad compresses to the semicylindrical configuration shown as a dashed line. Thus the two resilient pads completely surround the battery post or the like, providing much more surface contact area than with prior art clamps.

In each of the embodiments previously discussed, the force F with which the pads will squeeze the terminal which they grip will be seen to vary inversely with the distance of the terminal from the pivot point of the clamp, so that a terminal grasped by the nose end of the clamp will be gripped less tightly than one grasped near the pivot or hinge of the connector. FIG. 8 illustrates how the compressive force with which a terminal is gripped may be made more uniform, no matter where along the length of the clamp the terminal is gripped. As shown in FIG. 8, resilient compressible wire pads 26 and 27, which are carried on rigid jaws which pivot about point P, are provided with thicknesses which vary along their length. When the clamp of FIG. 8 closes, it will be seen that the pads will be compressed more at their thicker outer edges than at their thinner inner edges, thereby tending to compensate for the difference in lever arm distance from pivot point P. By suitably varying the thickness of the pads, the pressure between the pads in the closed position may be made fairly uniform along the length of the pads. Perfect uniformity requires theoretically that the pad thicknesses vary with a slight curve.

It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained, and since certain changes may be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

I claim:

1. A detachable electrical connector for providing an electrical connection to an electrical conductor comprising, in

combination: a pair of rigid jaws; a flexible electrical lead wire connected to one of said jaws; spring means for urging said jaws together to clamp said electrical conductor between said jaws; and compressible, electrically-conductive wire pad means mounted on at least one of said jaws to be compressed against said electrical conductor with a predetermined amount of force determined by said spring means upon closure of said jaws to wipe said electrical conductor, said wire pad means comprising a plurality of resilient, electrically-conductive wires.

2. A detachable electrical connector according to claim 1 in which said pair of jaws have at least one pair of rigid mating edges which meet to limit the closure of said jaws, said compressible wire pad means being arranged upon closure of said jaws to be at least partially compressed between said jaws prior to the mating of said rigid edges.

3v A detachable electrical connector according to claim 1 in which said wires of said wire pad means comprise beryllium copper wires.

4. A connector according to claim 1 in which said wires of said wire pad means are non-circular in cross-section, providing wire edges which scrape said electrical conductor to provide improved electrical contact as said wire pad means wipes said electrical conductor.

5. A connector according to claim 1 in which said wires of said wire pad means comprise interwoven warp and woof wires.

6. A connector according to claim 1 wherein said wire pad means comprises a first compressible wire pad mounted on one of said jaws and a second wire pad mounted on the other of said jaws so that portions of said first and second pads are compressed against each other and surround said electrical conductor upon closure of said jaws.

7. A connector according to claim 1 having a lead wire connected to at least one of said jaws, said wires of said wire pad means being smaller in diameter than said lead wire.

8. A connector according to claim 1 in which each of said jaws includes a serrated edge.

9. A connector according to claim 1 in which said wire pad means is mounted solely on one of said jaws and adapted to be compressed against a rigid surface of the other of said jaws upon closure of said jaws.

10. A connector according to claim 1 in which said wire pad means includes an arcuate surface adapted to partially surround a cylindrical conductor.

11. A connector according to claim 1 in which said compressible wire pad means comprises a plurality of fine wires disposed across the surface of a compressible non-conductive pad,

12. A connector according to claim 1 in which said compressible wire pad means comprises a mesh of wires superimposed upon one or more wire springsv 13. A connector according to claim 1 in which at least one of said rigid jaws includes a rigid cylindrical external surface and said jaws of said connector are adapted to be inserted into an electrical jack having a cylindrical recess, whereby the resilience of said compressible wire pad means serves to urge said jaws apart and to urge said rigid cylindrical external surface against the inside of said recess to frictionally hold said connector in said electrical jack.

I4. A connector according to claim I wherein said first wire pad and said second wire pad are arranged to be compressed against each other upon closure of said jaws toward each other.

15. A connector according to claim 1 in which said spring means is operable to urge said jaws toward each other to a limit position in which rigid portions of said rigid jaws abut opposite sides of one portion of said conductor and said wire pad means is compressed against another portion of said conductor.

16. A connector according to claim 1 having adjustable stop means carried on at least one of said jaws for limiting the motion of said jaws toward each other.

7. A connector according to claim 1 in which at least one of said rigid jaws includes a pair of spaced-apart side flanges extending toward the other of said rigid jaws, and in which the wire pad means mounted on said one of said rigid jaws is situated between said side flanges.

18. A connector according to claim 1 in which each of said rigid jaws comprises one end portion of a respective rigid lever, and pivot means interconnecting portions of said rigid levers intermediate their ends for mounting said levers to pivot relative to each other, whereby squeezing the other ends of said levers together against the force of said spring means moves said jaws apart and releasing said other ends of said levers allows said spring means to automatically close said aws.

19. A connector according to claim 18 in which portions of said wire pad means vary in thickness as a function of their distance from said pivot means.

20. A detachable electrical connector for providing an electrical connection to an electrical conductor, comprising, in combination: a pair of jaws; compressible, electrically-conductive wire pad means mounted on at least one of said jaws to be compressed against said electrical conductor upon closure of said jaws, said wire pad means comprising a plurality of resilient electrically-conductive wires; spring means adapted to urge said jaws apart from each other; a first length of hollow tubing adapted to be slid longitudinally along said jaws to urge said jaws together against the force of said spring means; a flexible lead wire extending through said first length of hollow tubing and connected to at least one of said jaws; and a second length of hollow tubing extending inside said first length of hollow tubing and adapted to engage said jaws, said second length of tubing being slidable relative to said first length of tubing to move said first length of tubing relative to said jaws thereby to release said jaws.

* at a a 

1. A detachable electrical connector for providing an electrical connection to an electrical conductor comprising, in combination: a pair of rigid jaws; a flexible electrical lead wire connected to one of said jaws; spring means for urging said jaws together to clamp said electrical conductor between said jaws; and compressible, electrically-conductive wire pad means mounted on at least one of said jaws to be compressed against said electrical conductor with a predetermined amount of force determined by said spring means upon closure of said jaws to wipe said electrical conductor, said wire pad means comprising a plurality of resilient, electrically-conductive wires.
 2. A detachable electrical connector according to claim 1 in which said pair of jaws have at least one pair of rigid mating edges which meet to limit the closure of said jaws, said compressible wire pad means being arranged upon closure of said jaws to be at least partially compressed between said jaws prior to the mating of said rigid edges.
 3. A detachable electrical connector according to claim 1 in which said wires of said wire pad means comprise beryllium copper wires.
 4. A connector according to claim 1 in which said wires of said wire pad means are non-circular in cross-section, providing wire edges which scrape said electrical conductor to provide improved electrical contact as said wire pad means wipes said electrical conductor.
 5. A connector according to claim 1 in which said wires of said wire pad means comprise interwoven warp and woof wires.
 6. A connector according to claim 1 wherein said wire pad means comprises a first compressible wire pad mounted on one of said jaws and a second wire pad mounted on the other of said jaws so that portions of said first and second pads are compressed against each other and surround said electrical conductor upon closure of said jaws.
 7. A connector according to claim 1 having a lead wire connected to at least one of said jaws, said wires of said wire pad means being smaller in diameter than said lead wire.
 8. A connector according to claim 1 in which each of said jaws includes a serrated edge.
 9. A connector according to claim 1 in which said wire pad means is mounted solely on one of said jaws and adapted to be compressed against a rigid surface of the other of said jaws upon closure of said jaws.
 10. A connector according to claim 1 in which said wire pad means includes an arcuate surface adapted to partially surround a cylindrical conductor.
 11. A connector according to claim 1 in which said compressible wire pad means comprises a plurality of fine wires disposed across the surface of a compressible non-conductive pad.
 12. A connector according to claim 1 in which said compressible wire pad means comprises a mesh of wires superimposed upon one or more wire springs.
 13. A connector according to claim 1 in which at least one of said rigid jaws includes a rigid cylindrical external surface and said jaws of said connector are adapted to be inserted into an electrical jack having a cylindrical recess, whereby the resilience of said compressible wire pad means serves to urge said jaws apart and to urge said rigid cylindrical external surface against the inside of said recess to frictionally hold said connector in said electrical jack.
 14. A connector according to claim 1 wherein said first wire pad and said second wire pad are arranged to be compressed against each other upon closure of said jaws toward each other.
 15. A connector according to claim 1 in which said spring means is operable to urge said jaws toward each other to a limit position in which rigid portions of said rigid jaws abut opposite sides of one portion of said conductor and said wire pad means is compressed against another portion of said conductor.
 16. A connector according to claim 1 having adjustable stop means carried on at least one of said jaws for limiting the motion of said jaws toward each other.
 17. A connector according to claim 1 in which at least one of said rigid jaws includes a pair of spaced-apart side flanges extending toward the other of said rigid jaws, and in which the wire pad means mounted on said one of said rigid jaws is situated between said side flanges.
 18. A connector according to claim 1 in which each of said rigid jaws comprises one end portion of a respective rigid lever, and pivot means interconnecting portions of said rigid levers intermediate their ends for mounting said levers to pivot relative to each other, whereby squeezing the other ends of said levers together against the force of said spring means moves said jaws apart and releasing said other ends of said levers allows said spring means to automatically close said jaws.
 19. A connector aCcording to claim 18 in which portions of said wire pad means vary in thickness as a function of their distance from said pivot means.
 20. A detachable electrical connector for providing an electrical connection to an electrical conductor, comprising, in combination: a pair of jaws; compressible, electrically-conductive wire pad means mounted on at least one of said jaws to be compressed against said electrical conductor upon closure of said jaws, said wire pad means comprising a plurality of resilient electrically-conductive wires; spring means adapted to urge said jaws apart from each other; a first length of hollow tubing adapted to be slid longitudinally along said jaws to urge said jaws together against the force of said spring means; a flexible lead wire extending through said first length of hollow tubing and connected to at least one of said jaws; and a second length of hollow tubing extending inside said first length of hollow tubing and adapted to engage said jaws, said second length of tubing being slidable relative to said first length of tubing to move said first length of tubing relative to said jaws thereby to release said jaws. 